Method of electrolyzing streaming electrolytes.



J. G. PAULIN.

METHOD or ELEGTROLYZING STREAMING ELEGTROLYTBS.

APPLIOATION FILED APR.7, 1911.

Patented Mar. 18, 1913.

YA /lV MX I AV AY /Z @Mew/e4 entran sTATEs PATENT onirica.

Josue GABRIEL PAULIN, or LANDsKnoNA, SWEDEN.

METHOD OF ELECTROLYZING STREAMING ELECTROLYTES.

I Specification of Letters Patent.

Patented Marne, 1913.

Application filed April 7, 1.911. Serial No. 619,611.

To ad whom t may concern:

Be it known that I, JosUA GABRIEL PAULIN, a subject of the King of Sweden,

pure, without very. .complicated -or expensive apparatus being used.

The object of t-he invention is to make it possible to obtain pure products by effectively preventing any ion from passing from one electrode to the other.

The invention consists, chiey, in either causing the whole electrolyte to move with a quite uniform speed (for instance by using a suitable porous plate or diaphragm of most homogeneous character) in the direction of the electric current, or opposite thereto, :automatically controlling the said speed, and so arranging the electrodes that the current density will be the same in all parts of a section or layer of the electrolyte at right angles to the direction of the electric current, or in causing parts of the electrolyte to move with a comparatively great speed, which need not be regulated, i. e.

creating' currents of liquid in the anodel chamber or the cathode chamber or both said chambers, which in this case must be separated by highly porous plates.V

The invention further comprises certain novel features of proceeding and apparatus hereinafter more fully described and claimed. v

In the drawing, I have shown diagrammatically certain electric apparatus and appliances adapted to be used in carrying the invention into effect.

Figure I is a vertical section of a simple electrolytic cell adapted to be used in certain cases when the electrolyte is caused to move as a whole. Fig. II is a vertical section of an electrolytic apparatus adapted to be used for similar purposes. F ig.` III is a y diagram of a device for regulating the speed of movement of the electrolyte. Figs. IV and V are vertical sections of electrolytic apparatus adapted to be used for causing separate currents of liquid' to flow in the anode and' the cathode chamber.

Referring to the drawing, the elect-rolytic apparatus shown in Fig. I is arranged horizontally and the electrolyte caused to flow from the bot-tom upward, for instance from the cathode 1 to the anode 2. L"The Whole electrolyte is caused to move with a quite uniform speed, disturbing currents of liquid being prevented by the-vessel having one o-r more narrow parts 3 or bythe provision of one or more porous partitions or diaphragms. The quantity of anode product in a certain layer'near the cathode is pref-l erably controlled by an electrolytic regulating device based on the variations in the resistance or the tension of decomposition respectively effected for instance by changes in the osmotic pressure of the electrodes or the pressure by which the ions are caused to move in the solution. By this means the important result is gained that the cations between the electrodes may be made practically stationary relatively to the electrolytic cell if at the same time the current densityisequally uniformly distributed as the flow of liquid, whereas the anions obtain a greater speed than the absolute traveling speed so that theelectricity is transported between the electrodes through the anions only.

As an example I will now-describe in what mannerthe electrolysis of zinc sulfate may be performed.' The Aapparatus to be employed may be constructed as shown in Fig. II. It comprises a preferably cylindrical vessel a of clay or other suitable material and having a hollow bottom b'the inner'partc of which is perforated all over its surface. Thesolution of zinc sulfate is supplied at the bottom through a pipe ortube 4 and allowed to spread uniformly along thehorizontal cathode 5, then passes a porous plate 6 and the anode Tand runs off through an overflow tube 8. The speed of the liquid is regulated in such a manner that a small part of thetotal flow of liquid is removed through a tube 9 and caused to pass through a regulating device ot the kind set 'toi-th, VFor instance an electrolytic cell having one electrode oit platinum and one electrode of zinc and containing crystals of potassium difhromate. .in electric current ot' a eer tain strength is caused to tion' 'from an ele` ment il. (Fig. lll) through the cell C. "When the percentage ot acid is below a certain limit, a layer ot Zinc is deposited on the platinum. rl`he Variations in strength oi;l the current through a relay V connected in shunt to the cell (l may be used tor regulating the supply ot fresh electrolyte to the electrolyzer.

it is obvious that any .suitable` regulating` device may be used but l prefer to use an electrolytic regulator of the kind set forth. lt has been found that, it the percentage of sulfuric acid of the liquid Yliowing through the cell (l sinks below a certain limit. (0.25 per cent. at a current density in the cell ot about 1.5 amperes per square deeimeter), the electromotive torce suddenly decreases with one volt causing a sudden change of the current strength through the relay Y. which on account thereof closes or opens an electric circuit tor a strong cur rent acting to throttle or to open a valve. tor the supply of electrolyte. By this means the percentage of acid ot the solution drawn ott through the tube 9 is constantly kept at the said height (0.25 per cent).

lt is to be noted that it is not necessary to cause the electrolyte to more as a Whole with a regulated speed since as before stated similar results may be obtained by causing parts ot the electrolyte to more with a comparatively great speed. which need not be regulated(` i'. c. hy arranging separate cur rents oit liquid in the anode chamber and the cathode chamber`r either a current ot' 't'resh electrolyte in the anode chamber and a current ot cathode product in the cathode chamber (tor instance in eleetrolyzing htatll) or a current otl 'fresh electrolyte in the cathode chamber and a current o't` anode product in the anode chamber (tor instance. in electrolyzing ZnStl). said currents ot liquid being preferably caused to tlow in the direction ot the electric current or in the direction opposite. thereto, Also in this manner the traveling trom the anode chamber to the athode chamber or versa ot ions which may have a disturbing inliuence on the process (the output7 the purity oiZ the products7 ett-Q may be eitectively prevented. The speed o'tl the liquids need only be so great that the traveling ol. a certain ion to the anode or the cathode 'respectively is avoided. lt has been proved tl it. in such case `the travelii'ig oi" the said ion to the anode chamber or the cathode cham L .f ber respectively is prevented. in ori it my invention may be more fully unnew l will non' proceed to device scribe in Vwhat manner this modification ot my improved process may be carried into eittect.

Example l-EZcctroZg/Sz's of ein@ sulfae.- fr concentrated solution oit zinc sulfate is admitted under pressure at the bottom ot the electrolyzer (Fig. lV), which may have the sides (Z and bottom c, f constructed as hereinbefore described With reference to F ig. H, caused to spread all over the horizontally extending cathode 11, for instance by a porous plate, a filter of sand or the like7 and drawn oli' in a less concentrated condition through a tube l2. A. small portion ot' the solution (tor instance 1 per cent.) passes through the diaphragm 13 and escapes through a tube 14. By this means all diiiusion of anode liquid into the cathode chamber is prevented. Sulfuric acid is admitted through a tube 15, passes through the pertorated anode 1G and runs ott' in a more concentrated condition through the tube 17. P1 portion ot the said acid passes through the diaphragm 18 and is drawn oft through the tube 14. By this means all dittusion ot cathode liquid into the anode chamber is prevented.

ln the manner described the cathode is always kept surrounded by a concentrated, slightly acid solution of Zinc sulfate, and the zinc precipitates uniformly and compactly. At the same time pure sulfuric acid of a Varying concentration (for instance GO per cent.) is obtained, Without the resistance in the electrolyzer being too high.

Example .f-Electrolysis of sodium ciZorl for prod/icing caustic soda ma? @klm rivaHThe clectrolytic apparatus may be ar- `anged in substantially the same manner as that just described or in a vertical position (Fig. V). The solution ot sodium chlorid is admitted through a tube 19 into a eomparativcly fiat vessel haring vertical side walls 7i, preferably rectangular in shape, passes the anode 2() and is (the main portion thereof) drawn oftl at 21 in a less concentrated condition, While a small portion of Said solution passes through the diaphragm Q2 and runs oit' through a tube 28. A solution ot sodium hydroxid or caustic soda is admitted at 241, passes through the cathode shown in the form of a wire and through a porous partition 2G and is drawn oil through a tube 2 in a more concentrated condition9 While a po "en said solution passes through the diaphragm 28 and escapes through the tube L8. manner pure caustic soda. is obtained.

Ela/ample 3-2'Eccr'0ljz/.215s of sodium fader-ln using the eleetrolytic ap shown in Fig. il?, 'the cai in the cathode chamber moi/ed by a current ot caustic soda ai through ie tube i12/and tnroug 7. the tube in more concentrated condi- `through the diaphragm 13.

tion. A small portion of caustic soda passes The solution of sodium sulphate is admitted through the t-ube 14, passes through the diaphragm 18 and runs od through the tube 17. The speed of movement of the solution through the diaphragm is controlled by a regulating device, for instance of the kind hereinbefore set forth. The solution drawn off through the tube 17 thus consists of almost entirely pure sulfuric acid.

I claim:

1. The method of electrolyzing streaming electrolytes which consists in causing a cur-- rent of fresh electrolyte to flow toward and past one of the electrodes, and causing a solution of the product formed at the other electrode to flow toward and past the said latter electrode, substantially as and for the purpose set forth.

2. The method of electrolyzing streaming electrolytes which consists in arranging the electrodes in such a manner that the current density will be the same in all parts of a cross-section of the electrolyte, and causing the said electrolyte to move as a whole with an automatically controlled speed, substantially as and for the purpose set forth.

3. The method of electrolyzing streaming electrolytes which consists in arranging the electrodes in such a manner that the current density Will be the same in all parts of a cross-section of the electrolyte, and causing the said electrolyte to move as a whole with an automatically controlled speed in a direction determined by the direction of the electric current.

4. The method of electrolyzing streaming electrolytes which consists in separating the anode chamber and the cathode chamber by porous partitions, causing a current of fresh electrolyte to flow through one of said chambers, and causing a current of a solution of the product formed in the other chamber to pass through the latter, substantially as and for the purpose set forth.

5. The method of electrolyzing streaming electrolytes which consists in separating thel anode chamber and the cathode chamber by double partitions inclosing an intermediate chamber, and maintaining a somewhat lower pressure in the said intermediate chamber,

substantially as and for the purpose set forth.

density will 'be the same in all parts of a cross-section of the electrolyte, causing the said electrolyte to move as a whole, and controlling the speed of movement of the said electrolyte by causing a part thereof to pass through an electrolytic regulating device adapted to work by changes in the composition of the liquid admitted.

7. The method of electrolyzing streaming electrolytes which consists in separating the anode chamber and the cathode chamber by porous partitions, causing a'current of fresh electrolyte to flow through one of said chambers, causing a Vcurrent of a solution of the product formed in the other chamber to pass through the latter, and controlling the speed of movement of the fresh electrolyte by admitting a part thereof into an electrolytic regulating device adapted to work by' changes in the composition of the electrolytic bath therein.

8. rEhe method of electrolyzing streaming electrolytes which consists in separating the anode chamber and the cathode chamber by double partitions inclosing an intermediate chamber, maintaining a somewhat lower pressure in the said intermediate chamber, causing a current of fresh electrolyte to'pass through one of said chambers, and causing a current of a solution of the product formed in the other chamber to pass through the latter.

9. The method of electrolyzing streaming electrolytes which consists in separating the anode chamber and the cathode chamber by double partitions inclosing an intermediate chamber, maintaining a somewhat lower pressure in the said intermediate chamber, causing a current of fresh electrolyte to pass through one ofsaid chambers, causing a currentof a solution of the product formed in the other chamber to pass through the latter, and controlling the speed of movement of the fresh electrolyte by admitting a part thereof into an electrolytic regulating device adapted to work by changes in the composition of the electrolytic bat-h therein.

JOSUA GABRIEL PAULIN.

Witnesses:

HAROLD MOHLIN, RICHARD WEIBULE. 

